Preheat the oven to 350°F (175°C). Grease an 8-inch square baking pan.
In a medium bowl, beat the eggs until they are light and fluffy. Add the melted butter, granulated sugar, brown sugar, and vanilla extract and mix well.
In a separate bowl, sift together the cocoa powder, flour, baking powder, and salt. Slowly add the dry ingredients to the wet ingredients and mix until everything is combined.
Pour in the Kahlua and mix until everything is combined. Pour the batter into the prepared baking pan and spread it evenly.
Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Let cool before cutting into squares.
Interesting Facts
Kahlua is a Mexican coffee liqueur made from sugar, coffee, and rum.
Brownies were invented in the United States in the late 19th century.